fix memory leaks

cmd/arg.c

@@ -16,6 +16,27 @@ struct b_command_arg *b_command_arg_create(void)
 	return out;
 }
 
+void b_command_arg_destroy(struct b_command_arg *arg)
+{
+	if (arg->arg_name) {
+		free(arg->arg_name);
+	}
+
+	if (arg->arg_description) {
+		free(arg->arg_description);
+	}
+
+	if (arg->arg_allowed_values) {
+		for (unsigned int i = 0; arg->arg_allowed_values[i]; i++) {
+			free(arg->arg_allowed_values[i]);
+		}
+
+		free(arg->arg_allowed_values);
+	}
+
+	free(arg);
+}
+
 b_status b_command_arg_set_name(struct b_command_arg *arg, const char *name)
 {
 	char *n = b_strdup(name);